When a person moves from being centered upon their own group to accepting and acknowledging different groups, he or she often moves through several stages. Not everyone starts with the first stage; they may already be at a later stage. And people may skip stages and enter them in different orders.
I am going to draw from something I wrote a while back to describe these stages. Below one character is describing to two others the stages. She begins by talking about the wurst, a time when there was much conflict between various groups.
First Stage: Not acknowledging other groups
First let me talk about the wurst and what [people] were doing. [They] were very centered on their own group . . . , whatever they felt attached to. Their group was the center of their world and all was measured against it. They manifested this centeredness in several ways. The first way involved a radical ignoring of the differences. Some did not even acknowledge the existence of other groups. To make sure the other groups did not creep into their awareness, they separated themselves from the other groups. They simply denied that there were any differences out there. This allowed them to stay centered on their group.
Second Stage: Defending through asymmetry
In the second way, the differences were perceived but they were threatening so some created defenses. They called the other inferior; they literally put the other down; they considered the other as beneath them or lower. Or, the other side of that coin, they emphasized the positive of their group and declared themselves superior. Or they might do a flip-flop and begin to see their group as inferior and the other as superior - thus still centered on their group.
Third Stage: Trivializing of of differences
Third, some held on to notions of their group being the center of the world by declaring that the other groups were really not different. This one was particularly dangerous because it was based on the common denominator and could seem so reasonable. The problem was that it minimized very real differences that need to be acknowledged. It is certainly laudable to seek commonality but not when it means ignoring variety. The two must be realized in tandem. This trivializing of differences was simply another way of saying "the right group is my group" because they also believed "and all are like my group." They said such things as, "We all eat and sleep and drink so what's the problem?" The problem was that they were still evaluating the world as measured against their world view and hiding the differences behind the similarities - similarities, I might add, as defined by them.
Fourth Stage: Becoming group-relative
. . . Now for the crux of the problem. For the [land] to be the way some dreamed, the groups needed to move out of being group-centered. They needed to be group-relative. That means that they needed to see differences not as right or wrong, nor as good or bad. And to see that their own group is not the reality against which all else must be measured and judged. When a [person] is group-relative, the differences do not threaten and are not something to be defended against. Differences are accepted, and, we hope, valued. [People] want to learn the skills to get along with different groups.